Apparatus for adding moisture to air

ABSTRACT

Improved apparatus is provided for adding moisture to air. The apparatus includes hollow cabinet means, having an air inlet and outlet, and humidifier means for adding moisture to an air stream flowing between the inlet and outlet. The humidifier means includes evaporative media means mounted for movement across the air stream and through a moisture reservoir that is supplied with liquid, such as tap water or the like. In accordance with the present invention, means are provided for purging or draining fluidized material, such as tap water and the mineral salts precipitated therefrom, from the reservoir and these drain means include a fluid inlet that is connected to the reservoir via siphon means comprising conduit means including an inverted generally U-shaped section.

United States Patent Schulze, Sr.

[ 1 Feb. 22, 1972 [54] APPARATUS FOR ADDING MOISTURE 3,315,948 4/1967Martin ..261/D1G. 46

TO AIR Prima ExaminerTim R. Miles [72] Inventor: James L. Schulze, Sr.,Middletown, Ky. g Examiner steven R Markowitz [73] Assignee: GeneralElectric Company Attorney-Harry B. ODonnell, Ill, Francis H. Boos, Jr.,Frank ,Osc .W l F Filed: y 1970 Neuhauser arB addelandJosephB orman [21]Appl. No.: 34,495 [57] ABSTRACT lmproved apparatus is provided foradding moisture to air. [52] U.S.Cl. ..261/97, 26l/DIG. 46 The apparatusincludes hollow cabinet means, having an air lllt- Cl --B0ld 3/0 inletand outlet, and humidifier means for adding moisture to [58] Field ofSearch ..26l/DIG. 46, 97 an air tream flowing between the inlet andou[]e[ The humidifier means includes evaporative media means mountedReferences Clted for movement across the air stream and through amoisture UNITED STATES PATENTS reservoir that IS supplied with liquid,such as tap water or the like. In accordance with the present invention,means are pro- 3,339,902 9/1967 Martin ..26l/DIG. 46 vided for purgingor draining fluidized material, such as tap 3,456,927 9 a n t 81-....26l/DIG. 46 water and the mineral salts precipitated therefrom, fromthe 2,646,061 7/1953 o i m 261/97 reservoir and these drain meansinclude a fluid inlet that is 2,323,761 4/ 1958 f-9 connected to thereservoir via siphon means comprising con- 3,336,71 1 6/1968 wllhams 46duit means including an inverted generally U-shaped section. 3,481,58812/1969 Lobb ....26l/D1G. 46 3,430,823 3/1969 Hunsaker ..26l/DlG. 46 6Claims, 4 Drawing Figures 30 i 34' 3 1 72 t 2.5 g 3 a 42. I f 4O f I i4t 2 I I I. I I I I 1 I I I I 1 1 L4 4 i I 1 \I I I 8 S t PATENTEUFEB221972 INVENTOR. JAMES L. 5CHULZE,SR. 4-7

. mid.

ms ATTORNEY F'IG.3

APPARATUS FOR ADDING MOISTURE TO AIR BACKGROUND OF THE INVENTION Thisinvention relates to improved apparatus for adding moisture to air and,more particularly, to apparatus of this sort comprising hollow cabinetmeans having an air inlet and outlet, humidifier means includingevaporative media means mounted for movement across the air stream andthrough a moisture reservoir, and means for draining fluidized materialfrom the reservoir. The present invention is also concerned withproviding novel unitized means to serve both as the humidifier moisturereservoir and also to collect condensate that drips from cooling coilmeans located adjacent the humidifier.

Previously, one of the most distressing problems in designing apparatusfor adding moisture to air has been the disposal of the mineral depositsor salts that are precipitated from the tap water, which is generallyused as the humidifier moisture source liquid. These mineral deposits orsalts are precipitated onto the evaporative media means and into themoisture reservoir when the level of minerals in the moisture sourceliquid reaches and exceeds the saturation point. Of course, thesemineral deposits or salts must be removed from the reservoir, lest theyeventually fill the same and thus render the humidifier deviceinoperative. Heretofore, various means have been provided for removingthese salts or mineral deposits from the humidifier moisture reservoir.Some of these prior art schemes, such as those illustrated in U.S. Pat.No. Re. 26,243 and U.S. Pat. No. 3,315,948, provide means whichcontinually drain a portion of the fluid from the reservoir and thusrequire considerable expenditures for water. Others, such as thatdescribed in U.S. Pat. No. 3.456327, while providing for only periodicdraining of the reservoir, employ an air-operated drain valve which ismost complex in construction and operation and hence quite expensive toutilize. All of these prior art means have been expensive to build,operate and maintain and have been inefficient in operation whencompared with the present invention.

SUMMARY OF THE INVENTION In accordance with the present invention, ithas been found that the aforenoted prior art problems can be overcome bythe improved apparatus provided by the present invention. Basically,this apparatus includes hollow cabinet means, having an air inlet andoutlet, and humidifier means for adding moisture to an air streamflowing between the air inlet and outlet. The humidifier means includesevaporative media means mounted for movement across the air stream andthrough a moisture reservoir which is supplied with liquid, such as tapwater or the like. In accordance with one aspect of the presentinvention, means are provided for draining fluidized material, such asthe moisture source liquid and the mineral salts precipitated therefrom,from the reservoir and these drain means include a fluid inlet that isconnected to the reservoir via siphon means comprising conduit meansincluding an inverted generally U- shaped section. Preferably, valvedmeans are provided for supplying the liquid to the moisture reservoir,along with first control means for controlling the valved means tomaintain a level of liquid within the reservoir that is sufficientlyhigh to supply liquid to the media means but below the bight portion ofthe inverted section, and second control means for periodicallyoverriding the first control means and thus causing the valved means toadmit sufficient liquid into the reservoir to raise the fluid leveltherein above the bight portion and thereby initiate periodic purging ordraining of the fluidized material from the reservoir via thedrain'means.

In accordance with another aspect of the present invention, novelunitized means is provided to serve both as the humidifier moisturereservoir and also to collect condensate that drips from cooling coilmeans located adjacent the humidifier means.

BRIEF DESCRIPTION OF THE DRAWING The present invention is illustrated inthe accompanying drawing, wherein:

FIG. 1 is a somewhat schematic, partly sectioned, front elevational viewof an air conditioning unit employing a presently preferred form of thepresent invention;

FIG. 2 is a greatly enlarged fragmentary view showing certain details ofconstruction of the present invention illustrated in FIG. 1;

FIG. 3 is a view similar to FIG. 2, but illustrating an alternative formof the present invention; and,

FIG. 4 is a simplified, schematic wiring diagram showing an electricalcontrol circuit which may be utilized with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawingand, more particularly, to FIGS. 1 and 2 thereof, there is illustrated,somewhat schematically, an air-conditioning unit 10 incorporating apresently preferred form of the improved apparatus provided inaccordance with the present invention. As shown, the air conditioningunit 10 comprises a vertically arranged hollow cabinet 11, typicallyformed of sheet metal or similar material. The cabinet 11 includes a topwall 12, a bottom wall 13, left and right sidewalls l4 and 15, a rearwall 16 and a front wall which has been removed for purposes of clarityof illustration.

As shown in FIG. 1, the hollow cabinet 11 has an air inlet opening 17through its top wall 12 and an air outlet opening 18 through the lowerpart of its left sidewall 14, and electrically powered fan or blowermeans 19, having a suction port 19a and a discharge port 19b, aremounted within the lower portion of the cabinet 11' for conveying astream of air as indicated by the arrows 20 through the cabinet 11between the cabinet air inlet 17 and outlet 18. Of course, the cabinetair inlet 17 is connected by duct means 21 to the room return air inlets(not shown), while the cabinet air outlet 18 is connected by other ductmeans 22 to the room conditioned air outlets (not shown).

Although it should be understood at the outset that the improved meansprovided by the present invention may be used with various forms ofair-conditioning units, the particular form of air-conditioning unit 10illustrated in FIG. 1 is provided with generally conventional coolingcoil means 23 for removing heat from the air stream 20 flowing throughthe cabinet I1 and conventional heater means 24 for adding heat to theair stream 20, but is further provided with a presently preferred formof the novel humidifier means 25 which are constructed in accordancewith the present invention and will be described in greater detailhereinafter.

As somewhat schematically illustrated in FIG. I, the cooling coil means23 comprises a conventional evaporative cooling coil bundle 26 of theso-called split-system variety of air cooling system. The coil bundle 26is mounted within the hollow cabinet 1 1 by bracket means 27 fastened onthe interior of the upper part of the cabinet right sidewall 15 and isarranged to slope downwardly and leftwardly across the air stream 20,terminating at a point spaced above second bracket means 28 that arefastened to the interior of the cabinet left sidewall 14 and extendgenerally horizontally therefrom over the blower means 19. And, in theparticular form of the air-conditioning unit 10 illustrated in FIG. I,the heater means 24 is schematically shown as being mounted on the lowerpart of the cabinet rear wall 16 between the discharge port 19b of theblower means 19 and the cabinet air outlet opening 18. As notedpreviously, the heater means 24 is conventional and may be eitherelectrically powered or gas or oil-fired.

Turning now to the presently preferred form of the improved humidifiermeans 25 that is provided in accordance with the present invention andlooking especially at FIGS. 1 and 2 of the drawing, it can be seen thatthis presently preferred form includes evaporative media means 30,preferably in the form of an endless belt 31, which may be made ofvarious types of material, such as double-woven wire belting, porousfabric, open cell foam, or the like. As illustrated in FIGS. 1 and 2,the belt 3.1 is strung around a drive roll 32 and an idler roll 33,which are, in turn, spaced apart .from

one another and rotatably journaled in belt frame means 34 mountedadjacent to the cooling coil bundle 26 but upstream of the pattern ofairflow through the cooling coil bundle 26. As more specifically shownin FIG. 1, the upper edge of the belt frame means 34 is provided withhooklike first mounting means which are engageable with complementarysecond mounting means 36 provided on the upper edge of the cooling coilbundle 26, whereby the belt frame means 34 is supported by the coolingcoil bundle 26 which is, in turn, supported by the aforenoted firstbracket means 27 provided on the upper interior of the cabinet rightsidewall 15. Thus, the major planes of both the humidifier belt 31 andthe cooling coil bundle 26 are arranged generally parallel to oneanother with the belt 31 being movable across the air stream 20 andhaving its lower end wrapped around the lower one of the two rolls 32and extending downwardly and leftwardly to a point spaced below thelower left corner of the cooling coil bundle 26, but spaced above, andapart from, the second bracket means 28.

The structure thus far described requires means for collectingcondensate that drips downwardly off the cooling coil bundle 26 duringoperation of the air-conditioning unit 10 in its cooling mode, lest thisdripping condensate causes problems to equipment, such as the blowermeans 19, that is located within the lower part of the cabinet 11. And,reservoir means are required for supplying moisture to the belt 31 ofthe evaporative media means 30 which, in turn, adds this moisture of theair stream 20 flowing between the cabinet air inlet 17 and outlet 18.Heretofore, separate means have been employed to perform thesecondensate drip collecting and moisture reservoir functions. However, inaccordance with one aspect of the present invention, unitized means isprovided for performing both of these two functions. As shown in FIGS. 1and 2, this unitized means 40 comprises a single generally rectangular,panlike member which is provided with feet 41 that rest atop theaforenoted second bracket means 28 and is located in the space providedbetween this second bracket means 28 and the left bottom edges of theevaporative media means belt 31 and the cooling coil bundle 26.

In the form of the present invention illustrated in FIGS. 1 and 2,unitized means 40 has integrally formed weir means 42 which subdivide itinto a reservoir portion 43 that extends under the lower left edge ofthe evaporative media belt 31 and a condensate drip collection portion44 that extends under the lower left edge of the cooling coil bundle 26.The evaporative media belt 3] is moved across the air stream 20 andthrough the moisture reservoir portion 43 of the unitary means 40 byrotation of the drive roll 32 which is itself rotated by a drive belt 45that is connected to the rotary output shaft of an electric motor 46mounted on the exterior of the cabinet left sidewall 14.

As further shown in FIGS. 1 and 2, drain means 47 are provided fordraining fluid from the unitized means 40. As best shown in FIG. 2, thepresently preferred form of these drain means 47 includes first drainmeans comprising a first conduit means 48 having a first fluid inlet 49,which extends through an opening 49' provided at the bottom of the rightsidewall of the unitary means 40, and is directly connected to the dripcollection portion 44 of the unitized means 40 and second drain meanscomprising second conduit means 50 having a second fluid inlet 51connected to the reservoir portion 43 of the unitized means 40 viasiphon means that includes an inverted generally U-shaped conduitsection 52. The inverted U- shaped conduit section 52 has its bightportion 53 located above the first fluid inlet 49 but below the top ofthe weir means 42. More specifically, the first fluid inlet 49 isconnected to the drip collection portion 44 of the unitary means 40 justabove the bottom thereof and the remainder of the first drain meansconduit 48 extends rightwardly and downwardly therefrom with its outlet54 being connected to a sewer system (now shown). The second fluid inlet51 is vertically arranged over and spaced slightly above the bottom ofthe reservoir portion 43 of the unitary means 40 and forms a downwardextension of the left leg of the inverted U-shaped conduit section 52through which it is connected to the second drain means conduit 50. Thebight portion 53 of this inverted U-shaped conduit section 52 extendsthrough an opening 56 provided in the weir means 42, while the outlet 55of the second drain means conduit 50 forms an extension of the right legof the inverted U-shaped conduit section 52 and extends downwardlythrough an opening 57 provided in the bottom of the drip collectionportion 44 of the unitary means 40 and another opening 58 provided inthe second bracket means 28, and thence rightwardly and into connectionwith the first drain means conduit 48.

FIG. 3 illustrates an alternative embodiment 25a of the presentinvention, which is otherwise generally similar to the preferredembodiment 25 illustrated in FIGS. 1 and 2, except that the fluid inletfor the second drain means conduit 50 is also connected to the reservoirportion 43 of the unitary means 40 through an upright generally U-shapedconduit section 60. As shown in FIG. 3, the bight portion 61 of thisupright U-shaped conduit section 60 is located beneath the secondbracket means 28 and the right bottom of the reservoir portion 43 of theunitary means 40, while its left leg extends upwardly through openings62 and 63 which are respectively provided in the second bracket means 28and the bottom of the reservoir portion 43 of the unitary means 40. Theright leg of the upright U-shaped conduit section 60 extends upwardlyexternally of the unitary means 40 and is connected to the left leg ofan alternative form of inverted U-shaped conduit section 52a which isalso mounted externally of the unitary means 40 but has its bightportion 53a located at the same elevation as the aforenoted preferredform bight portion 53. With this alternative form 25a of the presentinvention (FIG. 3), only the openings 49', 62 and 63 need be providedand the need for openings 56, 57 and 58 is eliminated. Thus, thisalternative form 25a reduces the three fluidtight connections which re,of course, required between the drain means conduit sections and thethree openings 49', 56, 57 to only the one required at the opening 63.Furthermore, this alternative form 25a of the present invention has theadvantage of providing an S-shaped trap between the fluid inlet 51a andthe outlet 55 of the drain means conduit 50 that is connected to thereservoir portion 43 of the unitary means 40. Both of the aforedescribedembodiments 25 and 25a of the present invention are provided withsimilar means for supplying liquid, such as tap water or the like, tothe moisture source reservoir portion 43 of the unitary means 40 andcontrol means for controlling the input of this liquid to the reservoirportion 43 and for periodically purging or draining fluidized material,such as the moisture source liquid and the mineral salts precipitatedtherefrom, from the reservoir and out through the drain means 47 to theunshown sewer system.

Turning now to the drawing, with particular reference to FIGS. 1 and 4thereof, there are illustrated typical means which have been employedwith success to perform these lastmentioned functions of liquid supplyand control for both of the aforenoted embodiments 25 and 25a of thepresent invention. As illustrated, the means for supplying liquid to thereservoir portion 43 of the unitary means 40 comprises an electricsolenoid valve 70 of the normally closed variety, which is suitablymounted on the interior of the cabinet top wall 12. This liquid supplymeans valve 70 has its inlet connected through a supply conduit 71 to asource of liquid, usually tap water, well water, or the like (notshown), and has its outlet connected through a discharge conduit 72which extends downwardly over the top of the left end of the reservoirportion 43 of the unitary means 40. As best shown in the wiring diagramof FIG. 4, this normally closed liquid supply means valve 70 has itssolenoid 70s connected in electrical series with the normally opencontacts 73a and 73b of a thermally actuable switch 73 and the normallyclosed contacts 74a and 74b of a float switch 74 across a pair ofelectrical lines I. and L which, in turn, are connected across anelectric control power voltage source. As illustrated in FIG. 1, thethermally actuable switch 73 can be suitably mounted adjacent thecabinet air outlet 18 to thus sense the temperature of the air stream 20following the addition of heat thereto by the heating means 24. And, asbest shown in FIGS. 2 and 3, the float switch 74 can be mounted with itsfloat located within the reservoir portion 43 of the unitary means 40and arranged so as to maintain the level of liquid within the reservoirportion 43 at a so-called normal" level that is sufficiently high tosupply liquid to the lower left end of the evaporation media means belt31 but below the bight portions 53 or 53a of the inverted generally U-shaped sections 52 or 52a of the second drain conduit means 50 of eitherof the aforedescribed embodiments 25 or 25a of the present invention.

As further shown in FIGS. 1 and 4, the blower 19 has its motor 19mconnected across the electric control power source in electrical serieswith the normally open contacts 730 and 73b of the thermally actuableswitch 73 but in electrical parallel with the series-connected normallyclosed contacts 74a and 74b of the float switch 74 and the solenoid 70sof the normally closed liquid supply valve 70. Similarly, the drivemotor 46 for the movable evaporative media means belt 31 and an electricdrive motor 75m for an adjustable timer 75, that is mounted atop theupper right part of the cabinet top wall 12, are each connected acrossthe control power lines L, and L in electrical series with the normallyopen contacts 73a and 73b of the thermally actuable switch 73 but inelectrical parallel with the series-connected normally closed contacts740 and 74b of the float switch 74 and the solenoid 70s of the normallyclosed liquid supply valve 70. And, in further accordance with thepresent invention, there is provided a purge or flush switch 76 whichhas its normally open contacts 76a and 76b connected in electricalparallel with the float switch 74 and mechanically connected to thetimer through cam means or the like (not shown).

Prior to commencement of operation of the aforedescribed apparatus, thetimer 75 is manually set by the operation of means such as the rotaryhandle 75h shown in FIG. 1 to cause closure of the normally opencontacts 76a and 76b of the purge switch 76 periodically after theelapse of an adjustable predetermined length of time and to cause thesecontacts 76a and 76b to remain closed for an adjustable predeterminedlength of time. Following this, automatic operation of the apparatusthen commences when the temperature level around the thermally actuableswitch 73 at the cabinet air outlet 18 reaches the temperature levelrequired to actuate it to close its normally open contacts 730 and 73b.This energizes the blower motor 19m, the evaporative media belt drivemotor 46 and the timer motor 75m and, whenever the liquid level in thereservoir portion 43 of the unitary means 40 is below the aforenotednormal" level and the float switch contacts 74a and 74b are closed, alsoenergizes the solenoid 70s'to open the normally closed liquid inletvalve 70 and admit liquid therethrough into the reservoir portion 43until these contacts 74a and 7412 are opened by the upward movement ofthe float of the switch 74 as the liquid reaches the so-called normal"level.

As long as the temperature level around the thermally actuable switch 73remains sufficient to continue its actuation and maintain closure of itsnormally open contacts 73a and 73b and energization of the blower motor19m, evaporative belt drive motor 46 and the timer motor 75m, the airstream 20 will first be drawn downwardly from the room vents via thefirst duct means 21 and the cabinet air inlet 17 and through theevaporative media means belt 31, where it will receive moisture that isfirst acquired by the belt 31 during its movement through the liquidcontained in the reservoir portion 43. Next, the moistened air will moverightwardly and downwardly through the cooling coil bundle 26, then,leftwardly through the blower suction port 19a and out of the blowerdischarge port 19b and across the heating means 24 where it has heattransferred to it and, finally, back to the room conditioned-air ductsthrough the second duct means 22.

As the moisture is thus transferred from the reservoir portion 43 of theunitary means 40 to the air stream 20 via movable evaporative mediameans belt 31, the liquid level in the reservoir 43 will, of course,from time to time be reduced sufficiently to cause the float of thefloat switch 74 to move downward to reclose its contacts 74a and 74b andthus energize the solenoid 70s of the solenoid valve 70 long enough toadmit sufficient liquid through the liquid supply valve 70 to restorethe liquid level in the reservoir portion to the so-called normal level.Hence, it can be seen that the solenoid valve 70 comprises valved meansfor supplying liquid to the reservoir portion 43 of the unitary means40, while the float switch 74 comprises first control means forcontrolling the valved liquid supply means 70 to maintain the so-callednormal" level of liquid within the reservoir portion 43 that issufficiently high to supply liquid to the evaporative media belt 31 butbelow the bight portion 53 or 53a of the inverted generally U-shapedconduit section 52 or 52a of the drain means 47 that is provided fordraining the reservoir portion 43 of either of the aforedescribedembodiments 25 or 25a of the present invention.

If no control means other than the first control means 74 were providedfor controlling the valved liquid supply means 70, the humidifier means25 or 250 a might possibly be rendered inoperative by the salts ormineral deposits which might be precipitated onto the evaporative mediameans belt 31 and into the moisture reservoir portion 43 of the unitizedmeans 40 from the tap water, well water, or the like, that is generallysupplied to the reservoir portion 43 via the valved liquid supply means70, and thus clog the reservoir portion 43.

However, this potential clogging problem is avoided by theaforedescribed drain means 47 and by second control means which areprovided in accordance with the present invention for periodicallyoverriding the first control means 74 and thus causing the valved liquidsupply means 70 to admit sufficient liquid into the reservoir portion 43of the unitized means 40 to raise the fluid level therein above thebight portion 53 or 530 of the inverted U-shaped conduit section 52 or520 of the second drain means conduit 50 of either of the aforenotedembodiments 25 or 250 and thus initiate flushing, purging and drainingof fluidized material, such as the moisture source liquid and themineral salts precipitated therefrom, from the reservoir portion 43 viathese siphon means 52 or 520 and second drain means 50 to the unshownsewer means. More specifically, the second control means comprise theaforedescribed flush or purge switch 76 that is connected in electricalparallel with the first control means float switch 74 and isperiodically actuated by the timer 75 after the elapse of an adjustablepredetermined length of time to close its normally open contacts 76a and76b and to cause these contacts 76a and 76b to remain closed for anadjustable predetermined length of time that is manually preset by theoperation of means such as the timer handle 75h as indicated above. Withthis arrangement, the second control means 76 can be operated by thetimer 75 to override the first control means 74 and thus temporarilytake away control of the valved supply means 70 from the first controlmeans 74, so that the valved liquid supply means 70 can be periodicallycaused to admit sufficient liquid into the reservoir portion 43 of theunitized means 40 to raise the fluid level therein above the bight portion 53 or 53a of the inverted Ushaped section 52 or 52a of the seconddrain means conduit 50 of either of the aforedescribed embodiments 25 or25a of the present invention and thereby initiate flushing and drainingof fluidized material, such as the moisture source liquid and themineral salts precipitated therefrom, through the second drain means 50via the siphon means 52 or 52a for discharge through the combined drainmeans outlet 54 into the system (not shown).

Preferably, the relative sizing of the valved liquid supply means 70 andthe second drain and siphon means 50 and 52 or 52a is arranged such thatthe rate of fluid drainage via the second drain means 50 should exceedthe liquid input rate via the valved liquid supply means 70. It shouldbe noted, however, that should the rate of liquid input into thereservoir portion 43 exceed the rate of fluid drainage through thesecond drain means 50, the fluid can spill over the top of the weirmeans 42 and be subsequently discharged to the unshown sewer system viathe first drain means 48 and the outlet 54 of the combined drain means47.

It should, of course, be understood that the frequency and duration ofthis flushing or purging period should be varied in accordance with thelevels of concentration of the mineral deposits or salts in theparticular moisture source liquid that is employed. Good results havebeen achieved when using tap water supplied by the Louisville, Kentucky,Water Company as the moisture source liquid by setting the timer 75 tooperate to close second control means purge switch contacts 76a and 76bfor a 6-minute interval after each 8-hour period of closure of thenormally opened contacts 73a and 73b of the thermally actuable switch73. This can be varied through manual means such as operation of thetimer handle 75h, with the length of the flushing or purge period beingmade greater and more frequent. when using a moisture source liquidcontaining higher concentrations of mineral salts, or shorter and lessfrequent for source liquids containing lesser concentrations of mineralsalts.

It should further be understood that the aforedescribed operation isconcerned only with the heating mode of the air conditioner 10.Obviously, it is not intended that the normally open contacts 730 and73b of the thermally actuable switch 73 should be closed during thecooling mode of the air-conditioning unit. Thus, it should be understoodthat, during this cooling mode, these contacts 73a and 73b are intendedto remain open and thus prohibit operation of the valved liquid supplymeans 70, the timer 75, the evaporative media belt means drive motor 46,or the blower motor 19m by the circuitry illustrated in the wiringdiagram of FIG. 4. During this cooling mode, it is intended that theunitized means 40 shall serve only to collect condensate that dripsdownwardly from the cooling coil bundle 26 and into the drip collectionportion 44 thereof, from which the collected condensate is intended tobe drained through the first drain means 48 and discharged to theunshown sewer system via the outlet 54 of the combined drain means 47.However, it is to be noted, that, if the inlet 49 of the first drainmeans 48 should become clogged or blocked, the collected condensatecould ultimately overflow the weir means 42 and into the reservoirportion 43 and be subsequently drained from the unitary means 40 to theunshown sewer means via the second drain means conduit 50 and the outlet54 of the combined drain means 47.

It should be apparent to those skilled in the art that while there havebeen described what, at present, are considered to be presentlypreferred embodiment of this invention in ac cordance with patentstatutes, changes may be made in the disclosed apparatus withoutactually departing from the true spirit and scope of this invention. Itis, therefore, intended that the appended claims shall cover suchmodifications and applications as do not depart from the true spirit andscope of the present invention.

What is claimed is:

1. Apparatus for adding moisture to air, comprising:

a. hollow cabinet means having an air inlet and an air outlet;

b. humidifier means for adding moisture to an air stream flowing betweensaid inlet and outlet, said humidifier means including evaporative mediameans mounted for movement across said air stream and through a liquidreservoir;

0. valved means including an electrically powered valve for supplyingliquid to said reservoir;

d. drain means for draining fluid from said reservoir, said drain meansincluding a fluid inlet connected to said reservoir via siphon meanscomprising conduit means including an inverted generally U-shapedsection;

e. first control means for controlling said electrically powered valveto maintain a level of liquid within said reservoir sufficiently high tosupply liquid to said media means but below the bight portion of saidinverted section; and

second control means for periodically overriding said first controlmeans and thus causing said electrically powered valve to admitsufficient liquid into said reservoir to raise the fluid level thereinabove said bight portion and thereby initiate draining of fluid fromsaid reservoir via said drain means.

2. The invention of claim 1, wherein said media means comprises beltmeans.

3. The invention of claim 1, wherein said liquid comprises tap water.

4. The invention of claim 1, wherein the relative sizing of said valvedmeans and said drain and siphon means is arranged such that the fluiddrainage rate via said drain means should exceed the liquid input ratevia said valved means.

5. The invention of claim 4, wherein said fluid inlet for said drainmeans is also connected to said reservoir via conduit means including anupright generally U-shaped section.

6. The invention of claim 1, wherein said fluid inlet for said drainmeans is also connected to said reservoir via conduit means including anupright generally U-shaped section.

1. Apparatus for adding moisture to air, comprising: a. hollow cabinetmeans having an air inlet and an air outlet; b. humidifier means foradding moisture to an air stream flowing between said inlet and outlet,said humidifier means including evaporative media means mounted formovement across said air stream and through a liquid reservoir; c.valved means including an electrically powered valve for supplyingliquid to said reservoir; d. drain means for draining fluid from saidreservoir, said drain means including a fluid inlet connected to saidreservoir via siphon means comprising conduit means including aninverted generally U-shaped section; e. first control means forcontrolling said electrically powered valve to maintain a level ofliquid within said reservoir sufficiently high to supply liquid to saidmedia means but below the bight portion of said inverted section; and f.second control means for periodically overriding said first controlmeans and thus causing said electrically powered valve to admitsufficient liquid into said rEservoir to raise the fluid level thereinabove said bight portion and thereby initiate draining of fluid fromsaid reservoir via said drain means.
 2. The invention of claim 1,wherein said media means comprises belt means.
 3. The invention of claim1, wherein said liquid comprises tap water.
 4. The invention of claim 1,wherein the relative sizing of said valved means and said drain andsiphon means is arranged such that the fluid drainage rate via saiddrain means should exceed the liquid input rate via said valved means.5. The invention of claim 4, wherein said fluid inlet for said drainmeans is also connected to said reservoir via conduit means including anupright generally U-shaped section.
 6. The invention of claim 1, whereinsaid fluid inlet for said drain means is also connected to saidreservoir via conduit means including an upright generally U-shapedsection.